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Technical details on why DSL modem does not stay synched

[ Please no rantings about Verizon for this thread ]

I would greatly appreciate if a technically knowledgeable individual would explain why DSL modems lose synch with the central office. Sometimes the modem can stay connected all day without one interruption. And sometimes the modem will lose synch several times in one hour. Why does this happen? Is this just due to noise on the line or are there more technical explanations for this situation?

In my case, I have a Westell 6100G modem. My DSL service is 1 Mbps. These are my typical statistics

Transceiver Revision 3.3.2.2.0.1
Vendor ID Code 4D54
Line Mode ADSL_2plus
Data Path FAST

Transceiver Down Up
DSL speed 1184 447
Margin (dB) 31.5 29.9
Line attentuation 32.5 13.6
Transmit power 6.0 12.0

Thank you.

David

Comments

Hubrisnxs

the problem lies exactly the two bolded items.

You're downstream 1185 should be 1792 or something like that, that indicates that it's reached it's correct sync level and that it's maintaining that sync level. anything less than that indicates trouble on the line.

You may have a simple problem with one of your filters having gone bad. To test that, simply disconnect all the phones and filters, and retest the below numbers to see if they have changed, if they have changed then YES you have a bad phone or a filter. If they don't change then reach out to the link below, and ask for a switch to interleave provisioning, or if you can call in they can do it for you over the phone.

http://www.dslreports.com/forum/r21020955-Need-to-switch-between-Interleave-and-FastPath-Part-2

@David_3 wrote:
Transceiver Revision 3.3.2.2.0.1
Vendor ID Code 4D54
Line Mode ADSL_2plus
Data Path FAST

Transceiver Down Up
DSL speed 1184 447
Margin (dB) 31.5 29.9
Line attentuation 32.5 13.6
Transmit power 6.0 12.0
Thank you.
David

Hubrisnxs

@David_3 wrote:
Sometimes the modem can stay connected all day without one interruption. And sometimes the modem will lose synch several times in one hour. Why does this happen?
David

Basically the modem has a sliding scale as to the Variance in it's Signal to Noise Ratio. These are measured in Decibals.

The variance comes from line conditions, so typically this is affected by a lot of things, moisture in the air at night or in the morning, condensation on the telephone lines, heat and cold expanding and contracting the copper wiring, so depending on conditions in the field that are environemental in nature, the line will fluctuate it's signal. This particular problem is between the CO And your house only so there isn't a issue with other users affecting your service at all, but the quality of the line outside. There are several break points that a technician can look at to find the problem, and there are SEVERAL things that they could change in order to fix the problem, HOWEVER if they change it to interleave provisioning, it is designed to do auto correction on the line, and if the line is not severely affected, it will compensate and correct all those problems. There are instances where interleave provisioning can not fix those issues, and that means that your trouble could be more severe than you though, and then a VZ technician would have to go out and start isolating where the problem is. They will test in the Central office, in the outside plant and then ultimately back at your house.

8/10 times interleave provisioning will fix a problem like that for 1.5 mb customers and lower speed tiers. higher speed tiers are a little tricker.

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